1. Field of the Invention
The present invention relates to an optical member, a backlight assembly having the optical member and a liquid crystal display device having the optical member. More particularly, the present invention relates to an optical member capable of increasing luminance and decreasing a thickness, a backlight assembly having the optical member and a liquid crystal display device having the optical member.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) device displays images using liquid crystal having optical and electrical characteristics such as an anisotropic refractive index, an anisotropic permittivity, etc. The LCD device has various advantages such as thin thickness, lightweight structure, low driving voltage and low power consumption, compared with a cathode ray tube (CRT) type display device, plasma display panel (PDP) device, etc. Thus, the LCD device has been widely used in various industrial fields.
The LCD device includes an LCD panel that displays images The LCD panel does not generate light. Thus, the LCD device requires a backlight assembly that provides light to the LCD panel.
Most of conventional backlight assemblies usually employ a cold cathode fluorescent lamp (CCFL) having a thin and long cylindrical shape as a light source. However, a quantity of such CCFLs employed in the LCD device increases as a size of the LCD device increases. Thus, manufacturing cost of the LCD device increases, and optical characteristics of the LCD device such as luminance uniformity are lowered.
A flat-type fluorescent lamp that emits light in a surface shape has been developed in order to overcome the above-mentioned problems. The flat-type fluorescent lamp includes a lamp body divided into a plurality of discharge spaces so as to uniformly generate light in a broad area. The flat-type fluorescent lamp generates a plasma discharge in the discharge spaces in response to a discharge voltage provided from an inverter. A fluorescent layer inside the lamp body is excited in response to ultraviolet light that is generated by the plasma discharge of the discharge spaces to emit the visual light.
Since the flat-type fluorescent lamp includes the lamp body divided into the discharge spaces so as to effectively generate light, a dark line is observed between adjacent discharge spaces in which light is not generated. The conventional backlight assembly includes a light-diffusing plate so as to remove the dark line and improve luminance uniformity. The light-diffusing plate is spaced apart from a light-exiting face of the flat-type fluorescent lamp by a predetermined distance, for example, no less than about 12 millimeters (mm). However, when the light-diffusing plate having a relatively large thickness is disposed relatively far away from the flat-type fluorescent lamp, light loss increases and an overall thickness of the backlight assembly increases.